Hi team, I would like to appologize in advance for the disjointed post that follows. I have attempted research on this myself but I understand very little actual chemistry - so here I am humbly seeking assistance.
This is in part a follow up to a thread I came across from way back in 2011.http://www.chemicalforums.com/index.php?topic=51002.0
There is still no satisfactory answer (I have been able to locate).
What is causing the immediate feeling of nausea after ingesting fresh apples/avocado/tomato in so many people?
The first issue when searching for answers from the boards is that it is being attribute to oral allergies - in particular birch pollen/latex. But for me this doesn't fit - i don't believe this is an allergy in the sense it is not an autoimmune response.
The next suspect that gets thrown up is fructose and fodmaps. But I cannot find a correlation between the fructose in apples/avocado/tomato. Fructose malabsorption almost fits but due to the almost immediate onset of symptoms and lack of symptoms from other high fructose fruits it seems unlikely to be the cause.
I currently believe it may be related to fatty acids - in particular oelic and/or possibly linoelic. A/a/t all containing reasonably significant amounts - however again there are a number of other foods containing large amounts of these fatty acids which aren't causing nausea.
I'm assumimg stomach acid/digestive enzymes are at play here.
What I do know:
ingesting salt after the fruit will almost immediately resolve the symptoms of nausea.
Adding vinegar or lemon juice to the raw fruit will lessen the symptoms from intense to mild.
Cooking/heating the fruit before ingesting can totally eliminate the onset of symptoms.
Some important things I don't understand:
How would salt effect the acidity of stomach acid?
How cooking/heating would effect the fructose or fatty acid structure/concentration?
Is vinegar/lemon juice more likely to be effecting stomach acid or neutralizing a chemical in the fruit?
If you can shed some light on anything I have raised here it would be very much appreciated!